#include<reg52.h>
#define uchar unsigned char
#define unit unsigned int
sbit LED=P2^0;
void delayms (unit xms)
{
unit i,j;
for(i=xms;i>0;i--)
    for(j=110;j>0;j--);
}
 void main()
{
while(1)
 {
   LED=0;
   delayms(1000);
   LED=1;
   delayms(1000);
 }
   
}